Wokwi - Online ESP32, STM32, Arduino Simulator

#include <WiFi.h>
#include <LiquidCrystal_I2C.h>


LiquidCrystal_I2C lcd(0x27, 16, 2);

WiFiServer server(80);

String header;

#define NTP_SERVER     "pool.ntp.org"
#define UTC_OFFSET     3600
#define UTC_OFFSET_DST 3600 // posun o 1hod

struct tm cas;


int r = 5;
int g = 18;
int b = 19;


String cas_ulozenie;

unsigned long currentTime = millis();
unsigned long previousTime = 0; 
const long timeoutTime = 2000;

void setup() 
{
  Serial.begin(9600);
  pinMode(2,OUTPUT);
  lcd.init();
  lcd.backlight();
  pinMode(r, OUTPUT);
  pinMode(g, OUTPUT);
  pinMode(b, OUTPUT);
  
  WiFi.begin("soc2019","socka2019");
  while(WiFi.status() != WL_CONNECTED)
  {
    delay(250);
    Serial.print(".");
  }

  Serial.println("WiFi uspesne pripojena!");
  Serial.print("IP adresa: ");
  Serial.println(WiFi.localIP());

  server.begin();
  configTime(UTC_OFFSET, UTC_OFFSET_DST, NTP_SERVER);
}

void loop()
{
  lcd.setCursor(0,1);
    lcd.print(vypisCas());
  WiFiClient client = server.available(); // aktualizovanie prijatych dat

  if (client) // ak sa pripojil klient
  {
    currentTime = millis();
    previousTime = currentTime;
    Serial.println("Novy klient");
    String currentLine = ""; // premenna pre prijate data
    while (client.connected() && currentTime - previousTime <= timeoutTime) 
    { 
      currentTime = millis();
      if (client.available()) // test ci su prijate dake data
      {
        char c = client.read(); // nacitanie bajtu z buffera
        Serial.write(c);
        header += c;

        if (c == '\n') // po ENTER je request 
        {
          if (currentLine.length() == 0) // ak sa nacital prazdny riadok, odosli potvrdenie o spojeni
          {
            client.println("HTTP/1.1 200 OK");
            client.println("Content-type:text/html");
            client.println("Connection: close");
            client.println("");

            client.println("<!DOCTYPE html><html>");
            client.println("<head><style>body { font-family: Arial, sans-serif; text-align: center; margin: 0; padding: 20px; background-color: #f0f0f5; color: #333; } button { padding: 12px 24px; font-size: 16px; border: none; border-radius: 8px; cursor: pointer; color: white; margin: 10px; transition: opacity 0.3s, transform 0.2s; } button:hover { opacity: 0.9; transform: scale(1.05); } a[href=\"/led/R\"] button { background-color: red; } a[href=\"/led/G\"] button { background-color: green; } a[href=\"/led/B\"] button { background-color: blue; }</style></head><body>");
            client.println("<h1>ESP32 <a href=\"https://www.spsknm.sk/ssknm/\" target=\"_blank\">web</a> server</h1>");
            client.println("<p><a href=\"/led/R\"><button>Nastav</button></a></p>");
            client.println("<p><a href=\"/led/G\"><button>Nastav</button></a></p>");
            client.println("<p><a href=\"/led/B\"><button>Nastav</button></a></p>");
            
            client.println("<p><a href=\"/refresh\"><button>Refresh</button></a></p>");
            client.println("</body></html>");
            client.println("");
            break;
          }
          else 
          {
            currentLine = "";
          }
        } 
        else if (c != '\r') 
        {  
          currentLine += c;     
        }
      }
    }
    if (header.indexOf("GET /led/R") >= 0) {
      lcd.clear();
      vypni();
          Serial.println("Zapinam LED");
          lcd.setCursor(0,0);
          lcd.print("Cervena");
          digitalWrite(r, HIGH);
        } else if (header.indexOf("GET /led/G") >= 0) {
          lcd.clear();
            vypni();
          Serial.println("Zapinam LED");
          lcd.setCursor(0,0);
          lcd.print("Zelena");
          digitalWrite(g, HIGH); 
        } else if (header.indexOf("GET /led/B") >= 0) {
          lcd.clear();
            vypni();
          Serial.println("Zapinam LED");
          lcd.setCursor(0,0);
          lcd.print("Modra");
          digitalWrite(b, HIGH); 
        } else if (header.indexOf("GET /refresh") >= 0) {
            cas_ulozenie = vypisCas();
            }
        

            client.print("<h1>Je: ");
            client.print(cas_ulozenie);
            client.print("</h1>");
    header = "";
    client.stop();
    Serial.println("Klient je odpojeny.");
    Serial.println("");

    
  }
}
void vypni(){
  digitalWrite(r,LOW);
  digitalWrite(g,LOW);
  digitalWrite(b,LOW);
}


String vypisCas() 
{
  struct tm cas; 
  if (!getLocalTime(&cas)) 
  {
    Serial.println("PROBLEM SO ZISKANIM UDAJOV ZO SERVERU!");
    return "Chyba"; 
  }

  char casString[9]; 
  strftime(casString, sizeof(casString), "%H:%M:%S", &cas); 


  return String(casString);
}